Created By : awnish

Reviewed By : Rajashekhar Valipishetty

Last Updated : Apr 10, 2023

Use Radiation Pressure Calculator to obtain the radiation pressure inside and outside the sun. Simply provide the inputs such as type of surface, luminosity, distance and temperature and hit the calculate button to avail the output in a fraction of seconds with a lengthy explanation.

Type of surface:
Choose a Calculation
Value of x

How to Calculate Radiation Pressure?

The following are the steps to find the solar radiation pressure easily.

  • Make a note of the given details from the question.
  • Multiply the surface value with the luminosity and cos square of the angle.
  • Get the product of the square of the distance from the star, speed of light and 4π.
  • Divide the product from step 2 by step 3 to get the radiation pressure outside.
  • Multiply the 4 times of constant with the temperature to the power 4.
  • Divide it by 3 times of light speed to heck the inside the star pressure.

Radiation Pressure Formula

As electromagnetic waves carry energy, they can also carry momentum. This electromagnetic radiation is photons. The momentum of photons will be absorbed or reflected.

The radiation pressure is the pressure exerted on a surface because of the exchange of momentum between the object and the electromagnetic field. The solar radiation pressure is due to the sun radiation at closer distances.

This Radiation Pressure Calculator gives the pressure outside and inside the star.

The formula of radiation pressure outside the star is p = x * L * cos²(α) / (4 * π * R² * c)

The formula of radiation pressure inside the star is p = 4 * σ * TΓü┤ / (3 * c)


c is the speed of light

p is the radiation pressure

T is the temperature

R is the distance from star

σ is the Stefan-Boltzmann constant and σ = 5.670367 x 10-8 W/(m² - KΓü┤)

L is the luminosity of star

x is the type of surface

α is the angle between the light beam and the surface of absorbing / reflecting surface


Question: If the star surface is opaque, luminosity is 1 solar, distance is 1 au and inside temperature 6000000 K. Find the radiation pressure?


Given that

Type of surfae is opaque. So, x = 1

Luminosity = 1 solar luminosity

distance R = 1 au

Temperature T = 6000000 K

Outside sun radiation pressure p = x * L * cos²(α) / (4 * π * R² * c)

p = 1 x 1 x cos²(0)/(4 x 3.14 x 1 x 299792458)

= 4.54

Inside radiation pressure p = 4 * σ * TΓü┤ / (3 * c)

p = 4 * 5.670367 x 10-8 * (6000000)⁴ / (3 * 299792458)

= 327 GPa

Therefore, the pressure inside the star is 327 GPa, outside the star is 4.54 μPa.

Physicscalc.Com has got concepts like friction, acceleration due to gravity, water pressure, gravity, and many more along with their relevant calculators all one under one roof.

FAQ's on Radiation Pressure Calculator

1. What is meant by radiation pressure?

Radiation pressure is the mechanical pressure exerted on a surface due to the exchange of momentum between the object and the electromagnetic field.

2. What is the formula for radiation pressure?

The solar radiation pressure outside the star formula is p = x * L * cos²(α)/(4π * R² * c). Inside star radiation pressure equation is p = 4σTΓü┤/3c.

3. What is the radiation pressure on the earth surface?

We know that, power = force x velocity

pressure = force/area

force = power/velocity = (1.4 x 1000)/(3 x 108) = 4.66 x 10-6

Pressure = 4.66 x 10-6 N/m102 = 4.66 x 10-6 Pa

Therefore, the radiation pressure on surface of earth is 4.7 x 10-6 Pa.

4. How to use Radiation Pressure Calculator to get the solar radiation pressure?

To find the radiation pressure outside and inside the sun, give luminosity, distance, temperature details and press on the calculate button.